And it insists that, despite the passing of 40 years, it is absolutely determined that those responsible are hunted down.

It issued a statement following this week’s landmark meeting between Home Secretary Theresa May, Secretary of State for Northern Ireland Theresa Villiers and members of campaign group Justice4the21.

A Government spokesman said: “The Home Secretary and the Secretary of State for Northern Ireland held a constructive meeting with relatives of some of the victims of the 1974 Birmingham pub bombings, an appalling act of murder which, intolerably, remains unsolved.

“Both ministers made clear the Government’s absolute determination that those responsible for this heinous crime be brought to justice and committed to seek assurances that all avenues of investigation have been, and are being, exhausted to get to the truth.

“The Government’s deep and heartfelt sympathies remain with the families and friends of all those innocent people who lost their lives in the terrible atrocities committed in Birmingham on that day more than 40 years ago.”

The names of the 21 victims of the Birmingham pub bombings

Twenty-one people were killed and 182 injured when the suspected IRA bombs exploded in two city centre pubs on November 21 1974.

Six men wrongly convicted of the murders - the Birmingham Six - were released in 1991 after their convictions were overturned by the Court of Appeal.

An inquest opened days after the bombings was closed without hearing evidence in 1975 in response to the guilty verdicts.

And in 1994 then the Director of Public Prosecutions Barbara Mills is believed to have made all important case documents subject to a 75-year Public Interest Immunity Order, effectively locking them away until 2069.

Member of J4T21 described the meeting as “positive.”

They are campaigning for a new inquest for the victims and for the 75-year embargo placed on the documents to be lifted.

Julie Hambleton, whose 18-year-old sister Maxine was killed, said she would now “wait and see” what the Government’s response was.

Ms Hambleton said the meeting had gone “better than expected”.

“It was positive. The Home Secretary was very sympathetic and very responsive to everything we said, but then what else could she be?” she said.

The campaigner said the coronial route would give the families the best chance of getting answers to their questions.

“It will give us the opportunity to get to the truth and potentially justice at the end of the day, which is what we want,” she said.

Yardley Liberal Democrat MP John Hemming said an inquiry should be held into what happened.

“It needs to be looked at. What we need to do is to identify who committed the offence,” he said.